DO NOT MERGE: Enable switch access api to activate/open files in DocsUI.

Switch Access uses OnClickListener() on individual views to check
whether a view is "clickable" or not. If it is clickable, using
prev/next keys will highlight to these clickable views. Since DocsUI
used to simply trap touch events and did not have any OnClickListeners
on its list/grid child views, switch access was not able to pick up
these views as clickable views. Simply adding an OnClickListener() fixes
this particular bug, but then a regular touch using finger/mouse would
trigger both onClick() and OnSingleTapUp(MotionEvent), which causes
double-firing and lead to unexpected behavior.

This fix overrides two accessibility-related methods in the
recyclerView's layoutManager, which the recyclerView delegates to.
Switch Access should now be routed to the correct behavior (which opens the
file/doc).

Bug: 30077035
Change-Id: I380d7529fa041f7b4905170f43f28a4235dc118d